In many industrial and commercial environments, it is often useful to serially connect a number of electrical extension cords, or to connect an extension cord to an electrical device. In the home or office environment, plugs of electrical power cords for equipment such as vacuum cleaners, electric-powered lawn mowers, drills, lights, computers, and the like, are often coupled to receptacles and/or extension cords. The friction connections between coupling prongs of the plugs and the blades of the receptacles vary greatly and generally will not hold the cords together against anything more than moderate separation tugs. Similarly, in the commercial or industrial environment, tools are commonly connected by extension cords. At construction sites, these cords are often exposed to dust, mud and moisture and may be subject to significant separation tugs.
The inadvertent complete or partial separation of a plug from a socket is not only annoying, but can be dangerous. Particularly in industrial and commercial environments, if the plug and socket combination inadvertently disengages during use, such disconnection can cause down time and a potential safety hazard depending on the type of equipment the power was cut off from. Even if partial separation occurs, a short circuit could occur and result in a fire or shock.
Carpenters and others have often attempted to solve this separation problem by tying two cords together in a knot. This method is unsafe because it can weaken or break one or both of the cords at the cord ends, creating an electrical hazard. Additionally, knots snag when moving cords around corners and other objects. Tape has also been used to hold cords together. Although somewhat effective, it is often messy because it leaves a residue of adhesive on the connectors after the tape has been removed, and does not allow for quick or easy disconnection. Thus, different types of clips have been developed for securing two cords together, such as the ones disclosed in U.S. Pat. No. 6,012,940 to Wheeler, and U.S. Pat. No. 4,183,603 to Donarummo. These clips are generally a unitary piece of plastic that clips around each cord. However, such clips cannot be used to connect a power cord to an electrical outlet on a wall, are cumbersome, and not very effective in preventing partial separation.
A number clamps have also been developed for securing a power cord to an extension cord, such as the ones disclosed in U.S. Pat. No. 6,135,803 to Kovacik et al.; U.S. Pat. No. 5,732,445 to Stodolka, et al.; U.S. Pat. No. 5,328,384 to Magnuson; and U.S. Pat. No. 4,957,450 to Pioszak. Relatively simple clamps are generally constructed of a plastic strip that is held together with a hook-and-loop material or snap-fit. However, such devices become useless once the hook and loop material becomes too dirty to provide a reliable bond. Relatively complex clamps are generally constructed of two parts that lock together with a screw mechanism. While such clamps may be more reliable for some uses, they still have the drawback of being difficult to use if they become dirty. At construction sites, power cords often lay on the bare ground and can become caked with dirt and mud. Even if they remain clean, these clamps are often time consuming to attach and require manipulation of several parts, making them complicated to manufacture and difficult to use. Further, some of these clamping devices only work if they are attached to the cords during the manufacturing stage of the cord itself. Others must be detached from the cords if not in use, and therefore need to be moved when switching cords from one connection to another.
Devices or adapters with multiple electrical sockets have also been developed in an attempt to solve the inadvertent separation problem, such as the one disclosed in U.S. Pat. No. 5,931,702 to Fladung. The Fladung device can only secure one power cord to one extension cord (i.e. one male connection to one female connection). Thus, if there are five female connections and one male connection, only one female connection and one male connection are secured. Four of the five cords can still be inadvertently separated from the adapter. Further, the device requires the electrical cord to be pulled through an eyelet and wrapped about a post. This presents the same problems as tying a knot in the cord.
Other devices have been developed for securing a plug to an electrical wall outlet, such as the one disclosed in U.S. Pat. No. 4,457,571 to Lavine et al. The Lavine device consists of a cup-like housing that is open on the top and one side. The open side has flanges that slidingly engage slots on the face plate of a wall outlet. However, these devices require permanent attachment to wall outlets, forcing the user to purchase multiple sets. The separate parts for these devices could become lost, and if the housing is left on the receptacle while not in actual use, small children may be tempted to put small toys or liquids into the housing. Further, these devices will not work in conjunction with an extension-cord-to-power-plug connection.
Accordingly, a need exists for an easy to use, compact, and streamlined device that can prevent inadvertent disengagement of a cord from a wall outlet, an extension cord, a power strip, or other connection source.